EP1419874A1 - Fiber reinforced laminates and fabrication method therefore - Google Patents

Abstract

A fiber reinforced laminate (I) having at least two layers comprises one layer of an allylic-, acrylic- and/or methacrylic group containing polymer that is curable by irradiation with high energy light. An Independent claim is included for a process for the production of cured laminates (I) by irradiation of a polymer layer (A) with high energy light, application of a further layer (B) onto the cured polymer layer, comprising a fiber reinforced composition curable by radical polymerization and/or by irradiation with high energy light.

Description

The invention relates to fiber-reinforced laminates with at least two layers.

It is known to produce laminates, the reinforcing fibers and radical or thermal contain curable polymers. Unsaturated polyesters are usually used for this. This often contain large amounts of copolymerizable monomers, usually styrene, which in the mixture reduce the viscosity of the curable mixture and for good ductility, for example by casting, winding or laying. During processing, this can be made from styrene easily escape from the hardenable masses due to the large surface area; this causes environmental and OSH problems.

It is therefore the object of the invention to provide fiber-reinforced laminates and binders therefor To make available that do not require such admixture of styrene and molded articles smooth, attractive surfaces and good ductility in heat before the final Cure result.

The object is achieved by using binders at least for an outer layer, which can be hardened by irradiation with high-energy light.

The invention therefore relates to fiber-reinforced laminates with at least two layers, characterized in that an outer layer A 'contains a polymer A containing allyl, acrylic and / or methacrylic groups, which is curable by high-energy radiation, and an adjacent layer contains reinforcing fibers and a curable composition B ' comprising a polymer B selected from systems which can be polymerized by free radicals ( B1 ) and by irradiation with high-energy light ( B2 ).

The invention further relates to a method for producing hardened laminates, comprising the steps: (1) producing a hardened polymer layer A ' from a polymer A by irradiation with high-energy light, and (2) applying a further layer to the layer (1 ) produced layer A ', the further layer containing reinforcing fibers and a curable composition B' , which is produced by free-radical polymerization from a free-radically polymerizable system B1 and / or by irradiation of a system B2 with high-energy light.

The invention also relates to a method for producing shaped laminates, in which the not yet fully cured laminates in the heat and pressure the desired shape and then cured.

In particular, a molded body or a surface made of a smooth substrate is first coated with a layer Z which has an antiadhesive effect, this layer is then coated in step (1) with a composition which contains a substance A polymerizable by irradiation with high-energy light, whereby by Irradiation of the substance A is polymerized and thus cured, in step (2) the free surface of this layer is coated with a curable composition B ' containing a polymer B selected from radicals ( B1 ) and by irradiation with high-energy light ( B2 ) polymerisable systems and Reinforcing fibers, and the curable mass B ' is then at least partially cured, and then removed from the surface or the molded body for final curing.

The polymers A and B2 are independently selected from epoxy acrylates, urethane acrylates, melamine acrylates, polyether acrylates, polyester acrylates, the corresponding methacrylates and esters of other olefinically unsaturated acids and allyl group-containing polyesters or polyethers and mixtures thereof.

Epoxy acrylates are reaction products of epoxy resins C with olefinically unsaturated compounds G containing carboxyl groups. Both the glycidyl ethers of dihydroxyaromatics such as resorcinol, dihydroxybenzophenone, dihydroxydiphenyl sulfone and preferably bisphenol A and bisphenol F can be used as epoxy resins C. it is also possible to use glycidyl ethers of aliphatic diols such as butanediol and hexanediol, as well as higher molecular weight epoxy resins, which are preferably made from bisphenol A and / or bisphenol F by the taffy process (reaction of these bisphenols with epichlorohydrin) and by the so-called advancement reaction ( Reaction of bisphenol diglycidyl ethers with the free bisphenols) are accessible. Epoxy resins based on novolaks and epoxidized oils can also be used.

Carboxyl group-containing olefinically unsaturated compounds G which can be used here are in particular acrylic and methacrylic acid, but also crotonic acid, vinyl acetic acid and the monoesters of olefinically unsaturated dicarboxylic acids such as monomethyl maleate, monomethyl fumarate and the monoalkyl esters of citraconic, itaconic and mesaconic acids. The first-mentioned acrylic acid and methacrylic acid are preferred.

Urethane acrylates are reaction products D (E) F of polyfunctional isocyanates D and hydroxyl group-containing olefinically unsaturated compounds F and optionally polyfunctional aliphatic alcohols E.

The polyfunctional isocyanates D are at least difunctional and can be selected from aromatic and aliphatic linear, cyclic or branched isocyanates, in particular diisocyanates. Diisocyanates are preferred, with up to 5% of their mass being able to be replaced by trifunctional or higher-functional isocyanates.

The diisocyanates preferably have the formula Q (NCO) ₂ , Q being a hydrocarbon radical having 4 to 40 carbon atoms, in particular 4 to 20 carbon atoms, and preferably an aliphatic hydrocarbon radical having 4 to 12 carbon atoms, a cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms, an aromatic hydrocarbon residue having 6 to 15 carbon atoms or an araliphatic hydrocarbon residue having 7 to 15 carbon atoms. Examples of such diisocyanates to be used preferably are tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 4,4'-diisocyanatodicyclohexylmethane propane, 4,4'-diisocyanatodicyclohexyl methane propane 2,2), 1,4-diisocyanatobenzene, 2,4- or 2,6-diisocyanatotoluene or mixtures of these isomers, 4,4'- or 2,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanatodiphenylpropane- (2, 2), p-xylylene diisocyanate and α, α, α ', α'-tetramethyl-m or p-xylylene diisocyanate and mixtures consisting of these compounds.

In addition to these simple polyisocyanates, those containing heteroatoms in which the isocyanate groups are also suitable linking rest included. Examples include polyisocyanates, the carbodiimide groups, Allophanate groups, isocyanurate groups, urethane groups, acylated urea groups or have biuret groups. Regarding other suitable polyisocyanates for example, to DE-A 29 28 552.

The optionally used polyfunctional aliphatic alcohols E have at least two Hydroxyl groups per molecule and 2 to 150 carbon atoms, preferably 3 to 40, and especially 4 to 20 carbon atoms. They can be linear, branched or cyclic, and can also foreign atoms, such as ether bonds, ester bonds or secondary or tertiary Amine bonds contained in the molecule. Such compounds are ether alcohols or Polyether alcohols such as polyethylene glycol, polypropylene glycol, their mixtures and copolymers and polyoxybutylene diol ("poly-THF"), as well as polyester alcohols and amino alcohols. Prefers glycol, 1,2- and 1,3-propanediol, 1,2- and 1,4-butanediol, neopentylglycol, 1,6-hexanediol, Trimethylolethane, glycerol, trimethylolpropane, erythritol, pentaerythritol, sorbitol, mannitol, Ditrimethylolethane, diglycerin, ditrimethylolpropane, diethylene glycol, triethylene glycol, di- and tri-propylene glycol, Diethanolamine, N-methyldiethanolamine, triethanolamine, ethoxylated Trimethylolpropane and ethoxylated glycerin.

1,4-Butanediol and 1,6-hexanediol are particularly preferred.

The hydroxyl group-containing olefinically unsaturated compounds F are aliphatic mono- or polyunsaturated compounds having 3 to 20 carbon atoms and at least one hydroxyl group. Allyl alcohol and the monoesters of dihydric alcohols F1 with the above-mentioned olefinically unsaturated acids G such as hydroxyethyl acrylate, hydroxyethyl methacrylate, 2- and 3-hydroxypropyl (meth) acrylate, 1-hydroxy-2-propyl (meth) acrylate are particularly preferred. acrylate, 4-hydroxybutyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate, esters of trihydric or polyhydric alcohols with an acid containing olefinically unsaturated groups, with at least one hydroxyl group remaining unesterified, for example trimethylolpropane di (meth ) -acrylate, pentaerythritol tri (meth) acrylate, and the acrylates and methacrylates which are formed by reacting (meth) acrylic acid with 1,2-epoxy compounds, in particular with esters or ethers of glycidyl alcohol with monohydric aliphatic alcohols or acids, which are preferred contain tertiary or quaternary carbon atoms. Such compounds are, for example, the esters of glycidyl alcohol with aliphatic monocarboxylic acids having 5 to 12 carbon atoms which are branched in the α-position.

Melamine acrylates are reaction products of hydroxyl-containing olefinically unsaturated compounds F with alkylolmelamines obtained by reacting melamine and aldehydes, in particular formaldehyde. In particular, the melamine acrylates are produced by etherification of hexamethoxymethylmelamine with the compounds F. It is also possible to etherify the compounds F directly with methylolated melamine, for example hexamethylolmelamine; however, this process is not carried out on an industrial scale.

Polyether acrylates are esters of polyalkylene glycols with degrees of polymerization of preferably 4 to 100, in particular polypropylene glycol, poly (oxybutylene-1,4) glycol and mixed copolymers with oxyethylene and oxypropylene units, with the olefinically unsaturated acids mentioned under G ; they are usually prepared by transesterification with ethyl (meth) acrylate or similar esters.

Polyester acrylates are esterification products of olefinically unsaturated acids G with hydroxyl group-containing polyols or polyesters or esterification products of hydroxyl group-containing olefinically unsaturated compounds F with acid groups of a polyester. The polyesters are usually of linear or branched aliphatic polyols with two or more hydroxyl groups and two to 20 carbon atoms such as glycol, neopentyl glycol, butanediol, 1,6-hexanediol, di- and tri-ethylene glycol, trimethylolpropane, pentaerythritol and sorbitol, aliphatic linear or cyclic Dicarboxylic acids such as adipic acid and cyclohexanedicarboxylic acid are derived, the hydroxyl-containing polyols from polyethers based on ethylene and propylene oxide or their mixtures, and from poly-tetrahydrofuran, and from ethoxylated and / or propoxylated polyhydric alcohols, such as those mentioned above.

Insofar as "acrylates" are mentioned above, these naturally also include the corresponding methacrylates and the esters of the other acids mentioned under G within the scope of the disclosure.

Compounds containing allyl groups are ethers or esters or mixed ether-esters of Allyl alcohol with polyhydric alcohols, their ethoxylation and / or Propoxylation products or allyl esters of the above-mentioned aliphatic carboxyl group-containing Polyesters.

The unsaturated polyesters B1 are styrene-free polyesters based on allyl ethers of polyhydric alcohols, the number of allyl groups always being one less than the number of hydroxyl groups of the unetherified alcohol, aliphatic linear, branched or cyclic diols with 2 to 20 carbon atoms, olefinically unsaturated dicarboxylic acids with 4 to 20 carbon atoms such as, in particular, fumaric acid, and small amounts of monohydric alcohols, in particular benzyl alcohol, the amount of the latter being such that the crosslinking by the polyunsaturated compounds is to be kept within limits.

Suitable reinforcing fibers are in particular glass fibers, but also carbon fibers, Aramid fibers, especially those made from the so-called high modulus polymers such as polyparaphenylene terephthalarnide (®Kevlar or ®Twaron) and copolymers (e.g. ®Teijin HM50) that contain over 30% of building blocks derived from terephthalic acid and para-phenylenediamine, as well Fibers made from liquid-crystalline polyesters and fibers made from ultra-high-molecular polyethylene (e.g. ®Dyneema).

For example, a conventional release agent (waxes, silicone-modified waxes, fatty acid amide waxes, salts of long-chain fatty acids such as zinc stearate, polyvinyl alcohol, fluorinated polymers and natural phospholipids such as soybean lecithin) can be used as the anti-adhesive layer Z.

The laminates according to the invention can be used in all applications in which hitherto Example laminates made of glass fiber mats with unsaturated polyesters with a gel coat surface were used.

Examples example 1

White-colored layers of radiation-curable mixtures according to Table 1 were applied to glass surfaces coated with soy lecithin as the anti-adhesive layer, in layer thicknesses of 600, 400 and 200 μm. The coatings were cured by irradiation with UV light (2 gallium-doped mercury lamps and undoped mercury lamps each with an arc length-related power consumption of 80 W / cm) at different throughput speeds through the radiation zone. Composition of the coating agent in g coating 1 2 3 4 5 6 7 unsaturated polyester 100 50 100 100 100 50 epoxy acrylate 50 50 urethane acrylate 100 color paste 10 10 20 20 20 20 20 photoinitiator .4,6 4.8 5 5 photoinitiator 5 4.8 5.2 ventilator 0.3 0.3 0.3 0.3 0.3 0.3 0.3 reactive 15 20 25 25 25 reactive 20 30 viscosity in mPas 1113 1567 803 1009 756 841 798

After curing at the stated belt speeds, an unsaturated polyester resin (®Viapal VUP 4782 / BEMT 55; co-peroxide system) reinforced with glass fiber mats was laminated onto the irradiated side, and then the structure was detached from the glass plate. The results summarized in Table 2 were obtained.

Example 2

In a second series of experiments, coatings 2.1 and 2.2 curable with UV light according to Table 3 were applied to glass plates coated with release agent as described above as described in Example 1. The coatings were cured at a belt speed of 5 m / min at a distance of 10 cm under 2 mercury lamps and 2 mercury lamps doped with gallium, each with a power consumption of 80 W / cm, detached from the glass plates and bonded to a UV light curable lamination layer. This layer consisted of a 10 × 20 cm ² glass fiber mat (approx. 5 g / m ² ), to which approx. 20 g of the UV laminating lacquers 2.3 and 2.4 were applied, as specified in Table 3. After the lamination, the laminate was cured by irradiation with UV light from the side of the impregnated glass fiber mat.

The results are summarized in Table 4. UV-curable coatings (compositions of the coatings in g) paint 2.1 2.2 2.3 2.4 unsaturated polyester ¹ 100 50 100 50 Epoxy acrylate ² 50 50 Photoinitiator ⁵ 5 5.2 5 5.2 Breather ⁶ 0.3 0.3 0.3 0.3 Reactive thinner ⁷ 25 25 Reactive thinner ⁸ 30 30 Color paste ⁹ 20 20 See Table 1 for explanations Results paint layer thickness hardening yellowing 2.1 600 µm cured not yellowed 400 µm 2.2 600 µm cured not yellowed 400 µm application rate 2.3 approx. 20 g on 10 × 20 cm ² cured not yellowed 2.4 approx. 20 g on 10 × 20 cm ² cured not yellowed

Example 3

In a third test series, glass fiber mats (10 × 20 cm ² ; approx. 5 g / m ² ) were applied to wood veneer (10 × 20 cm ² ) and laminations 3.1 and 3.2 curable with UV light were laminated in accordance with Table 5 (application amount 20 g / m ² ) and cured with 2 mercury lamps with a power consumption of 80 W / cm each at a belt speed of 10 m / min. This process resulted in a veneer-laminate composite material in a rational working step which, in a process according to the prior art, requires at least 2 working steps (producing the shape, for example an aluminum support) and fixing (gluing) the veneer to or on the corresponding form).

This molded part (= veneer-laminate composite) was then coated on the veneer side with a UV clear lacquer according to coating 3.3 (see Table 5), 2 layers and 3 layers of the clear lacquer having a wet layer thickness of 200 μm in each case being applied. The coating was cured again by exposure at a belt speed of 10 m / min with 2 mercury lamps with a power consumption of 80 W / cm each. The surface coated and hardened with the UV clear lacquer is equivalent to a polyester thick-layer lacquer, but it can be finished within a short time. In comparison, a polyester thick-layer coating for inlay work in automobiles (dashboard, steering wheel, gear stick handle) requires at least 6 to 7 jobs with an application amount of approx. 250 g / m ² each and possibly subsequent sanding / polishing / buffing; the total layer thickness at the end of processing is approx. 700 to 800 µm; The painting process takes approx. 4 to 5 hours, whereby the finishing by grinding and polishing can only take place 72 hours after the painting has been completed.

The results are summarized in Table 6. UV-curable coatings (compositions of the coatings in g) paint 3.1 3.2 3.3 unsaturated polyester ¹ 100 50 Epoxy acrylate ² 50 Urethane acrylate 3 85 Photoinitiator ⁶ 5 5.0 Photoinitator 11 4.7 Breather ⁶ 0.3 0.3 0.3 Reactive thinner ⁸ 25 10 Reactive Thinner ⁹ 30 See Table 1 for explanations Results paint layer thickness hardening 3.1 approx. 20 g on 20 × 10 cm ² cured 3.2 approx. 20 g on 20 × 10 cm ² cured 3.3 200 µm wet film cured

It turns out that styrene-containing unsaturated polyester resins with the classic radical curing by Cobalt salts and peroxides can be replaced by styrene-free UV-curable systems. The advantage of these systems is the freedom from styrene and the increased reactivity of the UV curable system and thereby higher productivity. Veneer-laminate composites can be applied using UV technology can be produced in one step. The use of a UV clear coat as a replacement for UP lacquer results in a significant increase in productivity through faster curing.

Claims (11)

Fiber-reinforced laminates with at least two layers, characterized in that at least one layer contains a polymer which has an allyl, acrylic and / or methacrylic group and can be hardened by irradiation with high-energy light. Fiber-reinforced laminates according to claim 1, characterized in that an outer layer A 'contains an allyl, acrylic and / or methacrylic polymer A which is curable by high-energy radiation, and an adjacent layer contains reinforcing fibers and a curable composition B. ' Containing a polymer B selected from free-radically ( B1 ) and polymerizable by irradiation with high-energy light ( B2 ) systems. Fiber-reinforced laminates according to claim 2, characterized in that the polymers A and B2 are selected independently of one another from epoxy-acrylates, urethane-acrylates, melamine-acrylates, polyether-acrylates, polyester-acrylates, the corresponding methacrylates and allyl group-containing polyesters and theirs mixtures. Fiber-reinforced laminates according to claim 2, characterized in that the polymers B1 are unsaturated polyesters which may contain styrene. Fiber-reinforced laminates according to claim 2, characterized in that the polymers B1 are selected from polyesters containing allyl groups and their mixtures with unsaturated polyesters based on fumaric acid. Fiber-reinforced laminates according to claim 1, characterized in that the first layer is a flexible film selected from veneers, polymer films and metal foils, and the second layer contains reinforcing fibers and the radiation-curable polymer A. Fiber-reinforced laminates according to claim 6, characterized in that the first layer is a veneer which, after the second layer has hardened, is coated with at least one coating hardened by irradiation with high-energy light. A method of making cured laminates according to claim 2, comprising the steps of: (1) making a cured polymer layer A ' from a polymer A by irradiation with high-energy light, and (2) applying another layer to those made in the step (1) Layer A ' , the further layer containing reinforcing fibers and a curable composition B' , which is produced by free-radical polymerization from a free-radically polymerizable system B1 and / or by irradiation of a system B2 with high-energy light. A process for the production of shaped laminates according to claim 2, characterized in that in the first step a molded body or a surface made of a smooth substrate is coated with a layer Z which has an antiadhesive effect, this layer is then coated in a second step with mass which contains a substance A which can be polymerized by irradiation with high-energy light, in the third step the substance A is polymerized by irradiation and is thus cured, in the fourth step the free surface of this layer is coated with a curable composition B ' containing a polymer B selected from radical ( B1 ) and by irradiation with high-energy light ( B2 ) polymerizable systems and reinforcing fibers, and in the fifth step the curable composition B 'is at least partially cured, and in the sixth step is detached from the surface or the molded body, the laminate formed subsequently by the action of Warmth and pressure k is deformed as long as the mass B ' is not yet fully hardened. Process for the production of laminates according to claim 6, characterized in that the film is covered with a layer containing reinforcing fibers impregnated by irradiation with high-energy light-curing polymer A , and the polymer-impregnated fiber-containing layer is then cured by irradiation. Process for the production of lacquered laminates according to Claim 10, characterized in that after the fiber-containing layer has hardened, the film is coated with a clear lacquer which can be hardened by irradiation with high-energy light.